Buddy

Buddy

An agentic AI crewmate that listens, reasons about the run, uses real game tools, remembers the session and slowly gets stranger.

Buddy is a voice-first AI crewmate for Lethal Company v81. He is not a scripted command bot. Talk naturally and the Realtime model receives fresh host-side game context, decides whether to answer or use one of Buddy's bounded tools, then reacts to the real result.

He can move with the crew, wait, scout, fetch scrap, return items to the ship, inspect crew and ship state, check moons and the store, buy equipment, and operate supported facility and ship controls. There is no command syntax to memorize.

Typed Lethal Company chat remains normal game chat and does not trigger Buddy or use API credit. Hold B to talk to him. Every compatible player can use voice.

Setup

• Install the same Buddy version on every player. installs BepInExPack and LethalSettings automatically.
• Add OpenAI API credit at the OpenAI Platform billing page. Buddy uses API billing separately from a ChatGPT subscription.
• Create a key at platform.openai.com/api-keys.
• In Lethal Company, open Settings > Mod Settings > Buddy, paste the key, press Save key, then Test key.
• Host a lobby with the same Buddy version installed for everyone.

Only the host needs an API key. It is stored in Windows Credential Manager and is never sent to clients.

Talk to him like a crewmate

Hold B and speak naturally. Buddy works from your intent and the current run instead of matching fixed phrases.

You can ask him to come with you, stay somewhere, scout ahead, bring back scrap, take things to the ship, tell you how the crew is doing, buy useful gear, or operate supported doors, turrets, mines, hangar doors and lights. The model chooses the appropriate bounded game tool when one is needed.

Each turn is grounded in live host-side context. The host executes supported actions and sends the real result back to the model before Buddy speaks, so he reacts to what actually happened instead of blindly announcing success. The model has no file, shell, process, credential or arbitrary-network access.

How the agent works

Buddy uses OpenAI gpt-realtime-2.1-mini only:

push-to-talk voice

|

v

gpt-realtime-2.1-mini

| live game context

| configurable thinking level

| bounded game tools

| native voice output

|

v

host game state -> real tool result -> Buddy's spoken reply

Thinking level defaults to low and is selectable in Buddy's settings (minimal, low, medium, high): lower answers faster and costs less, higher judges tool requests better but pauses longer before speaking. Spoken replies target 2-14 words: concise but not clipped. Responses run to the model's full output ceiling (max_output_tokens inf, gpt-realtime-2.1-mini's 32k maximum) shared between reasoning and speech, so a reply is never cut off mid-sentence by a token budget. Ordinary message audio starts as soon as Realtime identifies the output as a message. Tool-call audio remains buffered until the real host-side game result returns, so Buddy cannot announce a false success.

The Realtime session stays connected during play for conversational continuity, supplemented by bounded in-memory context. Buddy can therefore remember the current session, but this is not permanent chat storage. Typed chat never enters this model path.

Voice and multiplayer

• Buddy's voice is generated once by the host and synchronized to compatible clients.
• Remote push-to-talk audio is sender-bound, version/lobby-gated and rate/size/range limited. Public-lobby access is a separate host opt-in that defaults off.
• Normal Lethal Company voice chat is restored after Buddy push-to-talk releases the microphone.
• Clients never receive the API key.
• In orbit Buddy is a voice terminal without a body. His body appears outside only after the ship has landed and stopped.

Story and final stage

The slow-burn arc uses confirmed quota, round and witnessed-death evidence. It saves bounded numeric progress,